BorisDK1 wrote:Reignman wrote:yeah, it's quite funny actually. On top of that Boris has failed to answer a very important question that SS keeps asking. Yes, I read the above, and calling thousands of mins of data "noise" seems like a cop out answer here. Seems like everyone is pushing their own agenda and won't concede anything.
And lastly, if PDSS says Bargs is an above average defender or a top 3 defender amongst rotation guys on last seasons team then anyone with common sense should be questioning the data / formula used.
Reignman, I think you are engaging in misrepresentation about half as bad as Ripp.I have engaged what supersub has said, I've expressed my concerns that it is indirect analysis, that there is considerable noise (which supersub agreed with, but then said the noise somehow goes away when you go further back into the past), that despite admitting that on/off court data does not isolate one player (or even pass judgment on the quality of that player's defense) supersub has tried claiming that that actually happens just by including older data on teams past (which I believe to be untenable).
That aside, I am quite willing to engage that data. Lineups with Bargnani didn't do particularly well on the defensive end than other ones: I think we all get that. The point of PDSS is to further narrow down why that is the case: who gave up how much of what? is what it's trying to show. I am fully willing to consider and evaluate on/off court and APM data; by contrast, supersub and Ripp are 100% unwilling to even consider PDSS as having anything meaningful to say. So my question, is really - who's interacting less with their opponent? IMO, I think it can't be said that it's me...
At the end of the day, I keep coming back to the fact that we need to synthesize some data and at the end of the day, take the questions that the stats bring up (because stats provoke questions, not answers - you have to find the answers on the basketball court) and do business there. It seems supersub and ripp in this conversation up to this point aren't really doing that. And I'd love to get to there eventually, but it might take some time and some doing.
Thanks for the response Boris. To clarify, I love the work you've done and there is some great value in it. After mulling over the pros/cons of both PDSS and DRTG on/off I get the feeling that neither metric can truly capture the overall defensive capabilities of a player.
PDSS captures the 1 vs.1 stuff great; however, it can't differentiate between positions and positional defensive responsibilities / team defense. As we all know, different positions (particularly frontcourts) carry different burdens on defense. I realize you've tracked the data yourself but when it comes to help defense it becomes very murky and handing out grades can get very subjective.
In the same light, DRTG doesn't seem to be able to capture intricate details such as what was actually happening on the floor that caused one 5 man unit to be terrible while another isn't but it gives you an overall view (through deduction) of how some players fair. Now over a small sample size DRTG on/off can be very misleading but over 9000+ mins there has to be some merits to certain players that consistently show up positive over others that consistently show up negative. (After 9000 mins the variables really start to equalize for all rotation players)
Lastly, after reading / participating in this debate for the last 2 or 3 days it's funny that we've come to conclusions that we've already known. In 1 vs. 1 situations Bargs is pretty good but in situations where he needs to provide a ton of help (as has been the case more often than not with our shoddy perimeter D) you start to see some major holes in his game. I mean, there's a reason his own coach said he doesn't understand the concept of help D, why his GM is constantly talking about him improving his defense/rebounding and why opposing players/coaches like Gerald Wallace/SVG find the need to take pot shots at our frontcourt.
So while I agree that Jose doesn't make life any easier for Bargs (believe me, I've been talking about Jose and his faults for about 3 years now) I also believe Bargs himself needs to make tangible improvement with his help defense.
And how can PDSS "fail at lineup performance", exactly? It should predict individual performance of those players quite well, especially when you're looking at the individual elements of the DRat. Why might a given lineup vary? Limited sample size? Superior opposition? I don't know - and further, neither do you because as much as you might love APM or on/off court data, it doesn't tell you 
